1. Field of the Invention
The present invention relates to an apparatus for turning pages of a book, and a method for the same.
2. Description of the Related Art
Conventionally, a page turning apparatus is known which automatically turns pages of a book so that each page is photographed for book digitalization without the book being cut (for example, refer to Japanese Patent Application Laid-open (Kokai) Publication No. 2015-003446). In the mechanism of the page turning apparatus, an adhesion roller attached to an end portion of its arm is pressed against and adheres to a page of a book, and the page adhered to the adhesion roller is turned over by the rotational movement of the arm. By repeating this page turning operation by the rotational movement of the arm, the page turning apparatus turns the pages of the book one by one. Then, by photographing an unturned page by an imaging apparatus every time a page of the book is turned over, the page turning apparatus stores images of the pages of the whole book.
FIG. 6A, FIG. 6B, and FIG. 6C are schematic diagrams for describing a page turning operation by a general page turning apparatus. As shown in FIG. 6A, for an arm section 1 of this page turning apparatus, movable range A has been set such that the arm section 1 makes reciprocating motions between book stands 2-1 and 2-2. Also, a start point SP has been set on the book stand 2-2 side, and a return point HP has been set on the book stand 2-1 side. Here, a book 3 is fixed on the book stand 2-1 side of the page turning apparatus, as shown in FIG. 6B.
First, the arm section 1 is driven and rotated from the start point SP toward the return point HP side, and then an adhesion roller 4 attached to an end of the arm section 1 comes in contact with a page of the book 3. Here, the pressed page adheres to the adhesion roller 4. In addition, the arm section 1 is forcibly stopped distance B short of the return point RP by unturned page of the book 3, since it has been structured to make reciprocating motions within movable range A.
Next, when the arm section 1 is rotated toward the book stand 2-2 side, the page adhering to the adhesion roller 4 is turned over. Then, when the adhering page comes to the book stand 2-2 side along with the rotation of the arm section 1, it is removed from the adhesion roller 4 by the rotation of the adhesion roller 4 and the wind from an assist fan not shown, and guided to the book stand 2-2 side.
By this reciprocating motion of the arm section 1 between the book stands 2-1 and 2-2 pages on the book stand 2-1 side are turned over one by one toward the book stand 2-2 side. Also, by a page of the book being photographed by a tablet (smartphone) or the like every time a page is turned over, images of the respective pages of the book are captured.
In the beginning of the image capturing, there remain uncaptured pages on the book stand 2-1 side, so that the adhesion roller 4 is stopped at adhesion point AP1 based on the number of the remaining pages (thickness)), as shown in FIG. 6B. On the other hand, when the image capturing is ended, since there are no uncaptured pages on the book stand 2-1 side, the adhesion roller 4 is stopped at adhesion point AP2, as shown in FIG. 6C. That is, in the beginning and end of the image capturing, movable range A of the arm section 1 is restricted by an amount equal to the thickness of the book. In the middle of the image capturing, movable range A is restricted by an amount equal to the thickness of remaining uncaptured pages. Accordingly, pressing periods during which the adhesion roller 4 presses a page are different between that in the beginning of the image capturing and that in the end of the image capturing by an amount equal to a difference between distance 13 in FIG. 6B and distance C in FIG. 6C.
FIG. 7A and FIG. 7B are timing charts for describing a conventional page turning operation. In FIG. 7A and FIG. 7B describing the conventional page turning operation, (i) control signals IN1 and IN2 for an arm motor control section and (ii) electric currents in the arm motor in the beginning and end of image capturing are shown. In FIG. 7A and FIG. 7B, a rotation when the arm section 1 is driven and rotated from the start point SP to the adhesion point AP1 (AP2) is referred to as “normal rotation”, and a rotation when the arm section 1 is driven and rotated from the adhesion point AP1 (AP2) to the start point SP is referred to as “reverse rotation”.
In the case where the arm section 1 is driven and rotated from the start point SP to the adhesion point AP1 (AP2), control signal IN1 for the arm motor control section is set at “high level” and control signal IN2 is set at “low level” so that the arm motor performs “normal rotation”. Here, electric current in the arm motor gradually becomes small from the start of the driving until the adhesion roller 4 comes in contact with a page of the book 3. Then, when the adhesion roller 4 comes in contact with the page of the book 3, the arm section 1 is forcibly stopped, whereby an overcurrent is applied to the arm motor.
In general, in order to protect the arm motor from continuous overcurrent, a limiter for cutting the value of overcurrent to a predetermined value (1 A in the drawing) is operated. Then, by setting control signal IN1 for the arm motor control section at “high level” and setting control signal IN2 at “low level”, the arm motor control section causes the arm motor to perform “reverse rotation” so that the arm section 1 is driven and rotated from the adhesion point AP1 (AP2) to the start point SP. The above-described period during which overcurrent continues corresponds to a pressing period (locking period) during which the adhesion roller 4 presses a page of the book 3.
In the beginning of the image capturing, many remaining uncaptured pages are present on the adhesion point AP1 (AP2) side, as shown in FIG. 6B. Therefore, a driving period from the start point SP to the adhesion point AP1 (AP2) is 0.4 s−tPREM, and a pressing period (locking period) Ts during which overcurrent continues is 0.5 s+tPREM, as shown in FIG. 7A. Note that “tPREM” is a variable time based on the number of remaining uncaptured pages.
On the other hand, at the end of the image capturing, there are no remaining uncaptured pages on the adhesion point AP1 (AP2) side, as shown in FIG. 6C. Therefore, a driving period from the start point SP to the adhesion point AP1 (AP2) is 0.4 s, and a pressing period (locking period) Te during which overcurrent continues is 0.5 s.
As such, in the conventional page turning apparatus, there is a problem in that the locking period of the arm motor, or in other words, the pressing periods Ts and Te during which the adhesion roller 4 presses a page change depending on the thickness of the book, and the adhesion force of the adhesion roller 4 with respect to the page also changes. This problem becomes more apparent in the case of a thick book having many pages.
Also, the pressing periods Ts and Te during which the adhesion roller 4 presses a page cannot be controlled, and therefore the consumption of electric current is increased in the beginning of image capturing where the locking period of the arm motor that drives the arm section 1 is long, which extremely shortens the life spans of the brush and the coil of the arm motor.